Predictors of divorce and duration of marriage among first marriage women in Dejne administrative town

Divorce is a common occurrence in the marital lives of spouses. Consequently, numerous divorced spouses and their children face various social, economic, physiological, and health problems after breaking their marriage. This study aimed to identify the predictors of divorce and the duration of marriage. We conducted a community-based cross-sectional study among 423 randomly selected residents of Dejen Township in April 2020, of which only 369 respondents met the study inclusion criteria. We used structured questionnaires to collect data. The predictors of divorce and duration of marriage were analyzed using binary logistic regression and the Gompertz regression model, respectively. A p value less than 0.05 was used to express statistical significance. The prevalence of divorce was 21.14% [95% CI (19.01–23.27%)]. Half of these women broke up their marriage after 11 years. A high age difference (7 or more years) between spouses, an early marriage, infertility among women, the presence of third parties, women without formal education, women in the workforce, sexually dissatisfied women, women who did not live together with their husbands at the same address, partner violence, marital control behaviour of husbands, drug-abused husbands, spouses without children, and women who knew multiple sexual partners were the significant predictors of divorce. Partner violence, sexually dissatisfied women, women who made their own marriage decisions, marital control behaviour of husbands, women who did not live together with their husbands at the same address, drug-abused husbands and spouses without children were significant predictors of shorter marriage durations. In this study, the prevalence of divorce was high. Therefore, a community-based, integrated strategy is needed to minimize the divorce rate.


Sample size determination and sampling methods
The sample size was calculated using a single population proportion formula by conducting a pilot survey.The proportion of divorce among first-marriage women in the pilot survey was 40%, and we used a 5% error margin (d) and a 5% level of significance.Then the initial sample size was calculated to be 369.That is α/2 * P(1−P) d 2 = 1.96 * 0.4 * 0.6 0.05 2 = 369.Finally, we took into account a 15% non-response rate to determine the sample size.Subsequently, the sample size was 423.This sample size was proportionally allocated to each Kebele based on the number of households in each Kebel (Fig. 1).The town of Dejen is divided into two kebeles.We used this pre-arranged structure of the town to frame the current study.
Random sampling was utilized to choose study participants.Study participants were chosen from a list of households in the Dejen cities documented in the respective administrative units.We begin by randomly assigning a numeric code from one to two to each of the two kebles.Kebel 01 is 1, and Keble 02 is 2. We assign four-digit alphanumeric codes to each household in Kebele 01 and three-digit alphanumeric codes to each household in Kebele 02.For example, in Keble 01, there are 1398 registered households; therefore, the code for the first household was 0001, and the code for the last household was 1398.Kebele 02 had 932 households, with the first household having code 001 and the last having code 932.
Finally, among all households, randomly selected households have been selected using circular systematic sampling since N l = k l * n l

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, where as l is number of kebels in Dejen twon = 1, 2 .For example, the sample from Keble 01 was selected by applying circular systematic sampling.Circular systematic sampling consists of selecting a random number from 1 to 1398 using lottery methods and then selecting the unit corresponding to this random number.Subsequently, every unit is selected cyclically until a sample of units is obtained, k1 = N 1 n 1 , which is the nearest integer to 5.504, which is 6.Here, the first household of houses selected is 11, and then the women corresponding to this random number.Then, by applying the following formal, we selected the remaining household, and after that, the participant was selected from the selected household.
Similarly, Keble 02 samples were selected by applying circular, systematic sampling.Circular systematic sampling consists of selecting a random number from 1 to 932 using lottery methods and then selecting the unit corresponding to this random number.Thereafter, every unit is selected cyclically until a sample of units is obtained, k2 = N 2 n 2 , being the nearest integer to 5.515, which is 6.Here, the first household of random selection is 017, and then we have chosen the first respondent from this household.Then, by applying the following formal, we selected the remaining household, and after that, the participant was selected from the selected household.

Study variable
Dependent variables were divorce among first-marriage women (yes or no) and the length of time (measured in years) from the date of the first-marriage formulation to the date of divorce (event or censored).Independent variables were demographic variables (age, status of women's education), economic variables (unemployment status), sociocultural variables (early marriage, age difference between spouses, interference from third parties, marital control behaviour of husbands, history of partner violence against women, decision to marry, residing with husband at same address, number of children of spouse, fertility status, number of sexual partners, habit of discussion with husbands) and biopsychological variables (substance abuse, sexual satisfaction).

Operational definitions
Duration of marriage among first-marriage women means the length of time (measured in years) from the date of first-marriage formulation to the date of divorce (event or censored).
Censored means first marriage women who were not divorced until the data collection period, April 2020.
The event means first-marriage women who were divorced until the data collection period, April 2020.Experience of partner violence if women reported any of the specified acts of physical, sexual, or emotional violence committed by their husbands 35 .
Living with a husband means that a woman lives with her husband at the same address 36 .Substance abuse is a pattern of compulsive substance use marked by recurrent significant social, occupational, legal, or interpersonal adverse consequences, such as repeated absences from work or school, arrests, and marital difficulties.www.nature.com/scientificreports/Substance use is defined as the use of at least one substance (alcohol, khat, cigarettes, hashish, cannabis or heroin) during an individual's lifetime to alter mood or behaviour 37 .
Women had marital control behaviour when their husband showed at least one of the following controlling behaviours: being jealous or angry if he spoke to other men, frequently accusing her of being unfaithful, not allowing her to meet her female friends, attempting to limit her contact with her family and insisting on knowing where she is at all times 35 .

Ethics approval and consent to participate
Ethical approval was obtained from the Research Ethics Committee of the College of Natural and Computational Sciences (Debre Markos University) with protocol number NCS 4069/17/11.We confirm that all methods were carried out in accordance with relevant guidelines and regulations.Written informed consent was obtained from each participant prior to the interview.Participants who were unwilling to participate and wanted to withdraw at any stage of the interview had the freedom to do so without any restrictions.

Data analysis
Descriptive statistics were used to describe the percentage and frequency of women.The Kaplan-Meier survival function and log-rank test were used to estimate and compare the survival experiences of first-marriage women among the different groups of participants, respectively.The predictors of divorce among first-marriage women were analyzed using binary logistic regression.Predictors of the duration of marriage among first-marriage women were analyzed using the Gompertz accelerated failure time model.

Binary logistic regression analysis
We use binary logistic regression analysis to assess the predictors of divorce among first-marriage women.The specific form of the logistic regression model with unknown parameters, The binary logistic regression model can be rewritten as: where P i = the probability of divorce for the ith respondent, Y i = the observed marital status of the ith woman, and β is a vector of unknown coefficients.To estimate the values of the unknown parameters, we have used the maximum likelihood method of estimation.

Accelerated failure time model
We use an accelerated failure-time model to assess predictors of the duration of marriage among first-marriage women.The general accelerated failure-time model has the form: where µ is the intercept, x 1i , x 2i • • • x pi are the values of p explanatory variables of the ith woman.T i is denotes the observed failure time for the ith woman (i = 1, 2, • • • , n) , σ is the scale parameter, and ǫ i is denotes the ith observation error terms that have a standard probability distribution.Specifically, in this study, ε i is the best fit for the Gompertz distribution compared to other distributions because it has the smallest AIC and BIC compared to others (Table 1).
The hazard function for the Gompertz distribution can be written as follows: The parameter θ determines the shape of the hazard function.A positive value leads to a hazard function that increases over time.

Model-building strategy
To build the models, we first performed a bivariate analysis for each of the explanatory variables and, based on statistical significance, identified the variables as candidates for multivariate analysis at the 0.2 level of significance 38 .As naturally different factors or variables do not operate separately, multivariate analysis helps to control for confounders and analyze the effects of a factor in the presence of other factors in the model.In multivariate analysis, variables at a significance level of 0.1 were included in the model 39 .
We used Akaike and Bayesian information criteria to select the appropriate models, and the model with the smallest AIC or BIC was considered the best fit 40,41 .In addition, we used the Hosmer-Lemshow test statistic to evaluate the goodness-of-fit of the model for binary logistic regression, and the better the model fit is, the smaller the difference between the observed and predicted observations.

Characteristics of study participants
The analysis included a total of 369 participants who met the inclusion criteria.The median duration of marriage among first-marriage women (± interquartile range) was 11 years (± 13.5), ranging from 0.2 to 35 years.More than a quarter of women (32.2%) did not attend formal education, while more than three-quarters were orthodox followers (76.2%).About 30% of women reported experiencing some form of partner violence (emotional, physical, or sexual).Furthermore, approximately 30% of newly married women indicated that they had experienced at least one type of marital control behavior (Table 2).www.nature.com/scientificreports/

Prevalence of divorce among first-marriage women
A current study found that 21.1% (95% CI 16.8-25.2%) of women who had ever been married had experienced divorce.Women who had a habit of discussing with their husbands had a lower rate of divorce than women who did not have a habit of discussing with their husbands (16.1% vs. 35.8%)(Table 2).

Factors associated with divorce and duration of marriage
Age disparities of the spouse, age at marriage, fertility status, number of children, interference from third parties, educational status, sexual satisfaction, living with the husband at the same address, partner violence against women, marital control behaviour of the husband, husband who used substances and number of sexual partners of women who knew had a statistically significant association with divorce among first-marriage women at a level of significance of 0.05 (Table 3).The decision to marry, sexual satisfaction, living with the husband at the same address, partner violence against women, marital control behaviour of the husband, and the number of children had a statistically significant association with the duration of marriage among first-marriage women (Table 4).

Demographic variables
The study reveals that women who attended primary school (AOR 0.024, 95% CI 0.003-0.214)had lower chances of divorce compared to women who did not attend formula education.

Economic variables
This research indicated that the survival experience of first-marriage women had a statistically significant association with their employment status.Unemployed women have a longer survival experience in their first marriage than employed women (Fig. 2a-c).www.nature.com/scientificreports/

Socio-cultural variables
Women who were married at 18 years of age or older had a lower chance of divorce compared to women who were married at age < 18 years of age (AOR 0.027, 95% CI 0.003-0.258).Women who married husbands with an age difference of 7 years or more had a higher likelihood of divorce compared to those who married husbands with an age difference of 6 years or fewer (AOR 35.66, 95% CI 7.38-172.28).Women who did not have third party involvement in their marriage had a lower probability of experiencing divorce compared to women who had third party involvement [AOR 0.116, 95% CI (0.01-0.84)].Women whose husbands did not exhibit controlling behavior had a lower likelihood of experiencing divorce than those whose husbands did exhibit controlling behavior (AOR 0.091, 95% CI 0.025-0.332).Similarly, women whose husbands did not exhibit controlling behavior had a lower risk of divorce among first marriage women than those whose husbands did exhibit marital controlling behavior [AHR 0.480, 95% CI (0.236-0.706)].Furthermore, the study found that women who got married after discussing it with their parents had a lower risk of divorce among first-marriage women than those who decided to get married on their own decision [AHR 0.218, 95% CI (0.110-0.433)].
Women who did not report a history of some form of partner violence had a lower probability (AOR 0.214, 95% CI 0.032-0.476) of divorce compared to those women who reported a history of some form of partner violence.Similarly, women who did not inform of a history of some form of partner violence had a lower risk of divorce compared to those who reported a history of some form of partner violence [AHR 0.49, 95% CI (0.25-0.959)].However, women who had the habit of discussing with their husbands had a longer survival experience of marriage among first-married women than those who had no habit of discussing with their husbands Fig. 2a-c.
Women who did not live with their husbands at the same address had higher odds of divorce compared to those who lived together at the same address [AOR 82.48, 95% CI (14.43-471.46)].Women who had one or two children (AOR 0.001, 95% CI 0.0001-0.01)and those who had more than two children (AOR 0.002, 95% CI 0.0001-0.024)had lower odds of divorce compared to those women who had no children.In the same way, the risk of divorce for women who had one or two children and three or more children was 72.5% and 86% lower compared to women who had no children (AHR 0.275, 95% CI 0.151-0.508)and (AHR 0.14, 95% CI 0.072-0.274),respectively.Compared to infertile women [AOR 0.021, 95% CI (0.004-0.098)], those who were fertile had a lower chance of experiencing divorce.Similarly, fertile women also had a longer marriage survival experience among first-marriage women compared to infertile women (Fig. 2a-c).Women who knew two or more numbers of sexual partners had higher odds of divorce compared to women who knew only one number of sexual partners (AOR 7.123, 95% CI 1.83-26.943).

Biopsychological factors
Sexually satisfied women had lower odds of divorce compared to sexually unsatisfied women (AOR 0.084, 95% CI 0.023-0.309).Similarly, the risk of divorce for sexually satisfied women was approximately 51.9% lower compared to sexually unsatisfied women (AHR 0.481, 95% CI 0.248-0.9322).www.nature.com/scientificreports/Women whose husbands used substances had higher chances of divorce compared to those women whose husbands did not use substances (AIR 422.97, 95% CI 22.38-7992.84).Similarly, the risk of divorce for women whose husbands used substances was 48.8% higher compared to those women whose husbands did not use substances [AHR 1.488, 95% CI (1.01-3.384)].

Discussion
This research examined the predictors of divorce and the duration of marriage among first marriages in the Dejne administrative town, East Gojjam Zone.
The prevalence of divorce among women was 21.1% (95% CI 16.8-25.2%).This finding was consistent with the results of thirty-three sub-Saharan African countries and Ethiopia 4,6 .However, it is less than the study conducted in Gondar, Ethiopia (36.8%) and Bahir Dar, Ethiopia (46.5%) 42,43 .The difference observed between this and other studies could be the difference in the level of cities (this study was carried out in the administrative city of Woreda, whereas the previous study was carried out in regional metropolitan cities) and the difference in employment status; employed women have a higher prevalence of divorce 6,44 .
Women who completed primary school were more likely to divorce than those who did not attend formal school.This finding was consistent with previous investigations 4,6,45,46 .The possible reason for this study is that girls' education can raise women's marriage ages, and raising marriage ages would reduce divorce rates.Furthermore, educated women are less affected by external pressures when deciding on a marriage.
The findings of this research have shown that divorce of women has a statistically significant association with nine sociocultural variables: early marriage, the age difference between spouses, interference by third parties, marital control behaviour of husbands, history of partner violence against women, residing with the husband at the same address, number of children for the spouse, fertility status, and number of sexual partners.
Women without third-party influence were less likely to divorce than those with third-party interference.This study is in line with previous studies 8,9,42 .The possible reason for this study is that interference from third parties in the life of a married spouse is the main problem that hinders the continuation of marital relationships between spouses.
The chances of divorce were higher among women who were married at age < 18 years of age compared to women who were married at 18 or more years of age.This result is in line with prior findings 4,8,15,29,42,47 .The cause of this study could be a difference in maturity and marriage preparation.Furthermore, early married girls face sexual dysfunction in their later lives because they are more likely to have forced marital intercourse than those who marry later in life 48 .
Women who were married with an age difference of seven or more years between spouses had a higher risk of divorce than women who were married with an age difference of six or fewer years.This finding was consistent with previous findings 42 .The possible justification for this investigation is that the higher age difference between spouses is a cause of some difficulties, disagreements, and incompatible interests in their marital relationships, which can lead to divorce.
The odds of divorce were lower among women who had one or more children compared to those who had no children.Similarly, the chances of divorce were lower among women who were fertile compared to infertile women.This finding was in line with other studies 4 .The possible reason is that marriage is measured by the number of children they have in Ethiopia.Therefore, if marriage is not blessed by children, it is considered not to achieve its aim and a cause for divorce 49,50 .
Women who did not have marital control behavior of husbands had lower chances of divorce compared to women who did have marital control behavior of husbands.This result is similar to previous findings 8,47 .Women who did not have a history of partner violence were less likely to divorce than those who did.Other research has validated this finding 4,6,51 .The study could be justified by the fact that divorce is a last resort to deal with spousal violence if other techniques, such as correcting the causes of violence or living with the problem 52 .
The results of this study also revealed that divorce has a significant association with biopsychological factors such as substance abuse and sexual satisfaction.Women whose husbands were used to substance abuse had higher odds of divorce compared to women whose husbands were not used to substance abuse.The possible justification for this study is that most substance abusers are unable to perform what is expected of them.In addition, other side effects of substance abuse have also created many problems in their marital lives.
Sexually satisfied women had lower odds of divorce compared to those who were not sexually satisfied.This study is consistent with other studies 8,42,53 .The possible justification for this study is that sexual satisfaction contributes to healthy relationships and individual well-being.In addition, sexuality is an integral part of human life.
Unemployed women have a longer experience of first marriage than employed women.The finding of this study was similar to other studies 4,6,44 .The possible justification for this study is that unemployed women fear divorce due to their economic insecurity, which would increase the duration of marriage.Consequently, many unemployed women may have a problem in their marital life compared to employed women.
The risk of divorce for women who did not announce a history of some form of partner violence was 51% lower compared to those women who reported a history of some form of partner violence.Similarly, the risk of divorce for women whose husbands had no marital control behavior was 59.2% lower compared to those women whose husbands had marital control behavior.This result agrees with previous findings 8,54 .The likely explanation for the study is that the trust, respect, understanding, and equity relationship values they obtained from their husbands were critical to marital pleasure 55 , which may result in a longer marriage.
The risk of divorce for sexually satisfied women was approximately 51.9% lower compared to women who were not sexually satisfied.This result is in line with prior findings 8 .The study could be motivated by the fact that monotony, routine, and lack of variation hurt sexual activity in long-term relationships 56,57

Figure 1 .
Figure 1.Schematic presentation for the sampling procedure of the study Predictors of divorce and duration of marriage among first marriage women in the administrative Town of Dejne, April 2020.

Figure 2 .
Figure 2. (a-c) Kaplan-Meier survival estimates on the survival experience of women's marriage for categorical variables in Dejne Administrative Town, April 2020.

Table 1 .
Information criteria for the Parametric Survival Model on the predictors of duration of marriage among first-marriage women in the Administrative Town of Dejne, April 2020.

Table 2 .
Cross tabulation of divorce among first-marriage women with predictor variables in Dejne Administrative Town, April 2020.Df degree of freedom, P value probability value.

Table 3 .
Results of the binary logistic regression model with logit link for factors associated with divorce among first-marriage women in the Administrative Town of Dejne, April 2020.Ref reference, B estimated model coefficient, S.E standard error, Df degree of freedom, P value probability value, CI confidence interval, Exp (B) adjusted odds ratio (AOR).

Table 4 .
Results of the Gompertz accelerated failure time model for factors associated with duration of marriage among first-marriage women in Dejne administrative Town, April 2020.Ref reference category, AHR Adjusted Hazard ratio, S.E standard error, P value probability value, CI confidence interval.